This invention relates to a pet food, and more particularly to a soft dry pet food.
Within the class of pet foods, there are three basic types of pet food. A first type of pet food is a moist pet food generally having more than 50 percent by weight moisture therein. This pet food is highly palatable and requires aseptic canning conditions to stabilize the pet food for marketing purposes. A second type of pet food is a semi-moist pet food. The semi-moist pet food generally contains about 15 to about 50 percent by weight moisture. The semi-moist pet food does not require aseptic canning. It is stable when wrapped in standard polyethylene packages or other conventional packages. The semi-moist pet food requires no aseptic canning in order to be stable. A third type of pet food is the dry pet food. This pet food contains up to about 15 percent moisture by weight and is the most stable of the three classes of pet foods. By "up to" is meant at least some moisture is present. This pet food requires neither the aspectic canning of the moist pet food nor the wrapping of the semi-moist pet food. The dry pet food is merely put in bags or boxes and is unaffected by long periods of storage. This dry pet food maintains its characteristics over long periods of storage and is therefore easier to store and handle than either the semi-moist or the moist pet food. By moisture content is meant the total water content of the pet food, whether the water was added as free water, a component of the ingredients used in the pet food, or mixtures thereof.
While a dry pet food is additionally very nutritional, it nevertheless is not a particularly acceptable pet food in some cases to either the pet or the pet owner. The moisture content adds to the palatability of a pet food. The low moisture content of a dry pet food indicates a generally low palatability for the pet food. Furthermore, a dry pet food has a tendency to be hard to the point where it is unappetizing to both the pet owner and the pet. Furthermore, the appearance of a hard dry pet food detracts from its acceptability to both the pet owner and the pet. Thus, it may be seen that a dry pet food possibly has its storage advantages and nutritional advantages outweighed by inferior palatability and appearance.
Dry pet foods are commonly produced by preparing a farinaceous-proteinaceous mixture containing vitamins, minerals, fats, flavorants, colorants and water to a level of 20 percent to 40 percent by weight and cooking the mixture by use of a continuous extrusion-cooker whereby the dough is heated to 212.degree. F. to 300.degree. F. or more and expelled through a die, cut into bite size pieces, cooled, dried, and packaged. The elevated temperature is required to cook the starch and alter the mixture so as to form the typical hard, cohesive, dry pet food product.
Thus, conventional dry pet foods are typically hard and brittle. The hardness and brittleness is commonly imparted by the amylaceous and/or proteinaceous ingredients that are commonly used in conventional dry pet foods and which form essentially a continuous starchy and/or proteinaceous phase throughout the pet food; such starch and/or proteinaceous continuous phase being in a crystalline and/or a glassy state of matter. The continuous phase of crystalline or glassy matter in conventional dry pet foods is produced by the action of hydration -- dehydration during the heating processing at temperatures typically well in excess of the minimal temperature required to significantly hydrate starch and/or proteinaceous sources, and as a consequence of subsequent cooling and drying to the moisture levels typical in conventional dry pet foods.
There are some soft dry pet foods which are processed at temperatures and conditions which are similar to those used to produce conventional hard and brittle dry pet foods -- i.e. -- temperatures in excess of 212.degree. F. and which obtain their soft crumb structure by virtue of a plasticized expanded texture imparted by a unique combination of formula and process method. However, such expanded texture, albeit having a soft crumb structure, has the distinct appearance marketing disadvantage in that the expanded texture does not simulate the highly-desired texture of typical meat.
Furthermore at least one soft dry pet food is known which is not expanded and which is processed at temperatures of at least 145.degree. F., a temperature sufficient to significantly hydrate (gelatinize) amylaceous ingredients. However, this soft dry non-expanded pet food contains ingredients which are not as readily available as is required to provide an economical product. Furthermore, the amylaceous ingredients, if used, are used at limited levels, below the levels typically used in conventional dry pet foods.
Thus, it may be seen that problems still exist in the preparation of a dry pet food which is soft, more appetizing, palatable, and better appearing than the customary pet foods of the dry type known in the art.